In 2-3 complete sentences, analyze how scientists know dark matter and dark energy exist.

Answer:

Nuclear fusion

Explanation:

Answer:

The impact occured at a distance of 2478.585 meters from the person.

Explanation:

(After some research on web, we conclude that problem is not incomplete) The element "Part A" may lead to the false idea that question is incomplete. Correct form is presented below:

A person, with his ear to the ground, sees a huge stone strike the concrete pavement. A moment later two sounds are heard from the impact: one travels in the air and the other in the concrete, and they are 6.4 seconds apart. How far away did the impact occur? (Sound speed in the air: 343 meters per second, sound speed in concrete: 3000 meters per second)

Sound is a manifestation of mechanical waves, which needs a medium to propagate themselves. Depending on the material, sound will take more or less time to travel a given distance. From statement, we know this time difference between air and concrete ([tex]\Delta t[/tex]), in seconds:

[tex]\Delta t = t_{A}-t_{C}[/tex] (1)

Where:

[tex]t_{C}[/tex] - Time spent by the sound in concrete, in seconds.

[tex]t_{A}[/tex] - Time spent by the sound in the air, in seconds.

By suposing that sound travels the same distance and at constant speed in both materials, we have the following expression:

[tex]\Delta t = \frac{x}{v_{A}}-\frac{x}{v_{C}}[/tex]

[tex]\Delta t = x\cdot \left(\frac{1}{v_{A}}-\frac{1}{v_{C}} \right)[/tex]

[tex]x = \frac{\Delta t}{\frac{1}{v_{A}}-\frac{1}{v_{C}} }[/tex] (2)

Where:

[tex]v_{C}[/tex] - Speed of the sound in concrete, in meters per second.

[tex]v_{A}[/tex] - Speed of the sound in the air, in meters per second.

[tex]x[/tex] - Distance traveled by the sound, in meters.

If we know that [tex]\Delta t = 6.4\,s[/tex], [tex]v_{C} = 3000\,\frac{m}{s}[/tex] and [tex]v_{A} = 343\,\frac{m}{s}[/tex], then the distance travelled by the sound is:

[tex]x = \frac{\Delta t}{\frac{1}{v_{A}}-\frac{1}{v_{C}} }[/tex]

[tex]x = 2478.585\,m[/tex]

The impact occured at a distance of 2478.585 meters from the person.

Answer:

0 < r < r_exterior     B_total = [tex]\frac{\mu_o I}{2\pi r}[/tex]

r > r_exterior            B_total = 0

Explanation:

The magnetic field created by the wire can be found using Ampere's law

        ∫ B. ds = μ₀ I

bold indicates vectors and the current is inside the selected path

outside the inner cable

          B₁ (2π r) = μ₀ I

          B₁ = [tex]\frac{\mu_o I}{2\pi r}[/tex]

the direction of this field is found by placing the thumb in the direction of the current and the other fingers closed the direction of the magnetic field which is circular in this case.

For the outer shell

for the case   r> r_exterior

           B₂ = \frac{\mu_o I}{2\pi  r}

This current is in the opposite direction to the current in wire 1, so the magnetic field has a rotation in the opposite direction

for the case r <r_exterior

in this case all the current is outside the point of interest, consequently not as there is no internal current, the field produced is zero

           B₂ = 0

Now we can find the field created by each part

0 < r < r_exterior

          B_total = B₁

          B_total = [tex]\frac{\mu_o I}{2\pi r}[/tex]  

r > r_exterior

          B_total = B₁ -B₂

          B_total = 0

The average temperature of the air in the room at 20 min is 23°C.

Temperature is the degree of hotness or coldness of the object.

A student heated 235 g of water in a beaker until the water reached 100°C. The student removed the beaker from the heat and placed the beaker on a counter in a 23°C room. The student recorded the temperature of the water every 4 minutes for 20 minutes.

The surrounding is vast, its temperature does not get affected by small amount of water. So, the temperature of air remains constant.

Thus, the average temperature of the air in the room at 20 min is 23°C.

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Answer:

The nucleus-containing cells are called eukaryotic cells. Eukaryote means having membrane-bound organelles.

Explanation:

I hope this is what you were looking for?!

Hope this helps!

Have a great day!

-Hailey!

The cells which have a nucleus are called Eukaryotic cells. The cells which do not have a nucleus are called prokaryotic cells.

The nucleus is the controlling center of the body. It performs all the major activities in the cell. The cell which possesses a nucleus is called a eukaryote. The cell which does not have a nucleus is called prokaryote.

A prokaryotic cell is a straightforward, one-celled (unicellular) organism that is devoid of a nucleus or any other organelle that is membrane-bound. The nucleoid, a dark area in the center of the cell, is where prokaryotic DNA is located.

Therefore, The cells which have a nucleus are called Eukaryotic cells. The cells which do not have a nucleus are called prokaryotic cells.

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Answer:

shortest - gamma Ray's

size of a pencil tip : most likely microwaves

longest - radio waves

Gamma rays have the shortest wavelength whereas Radio waves have the longest wavelength. The wave whose wavelength is about the size of the tip of a pencil is infrared ray.

The whole electromagnetic waves are divided into several classes based on their frequencies or energies as follows, in the order of increasing frequency:

Radio waves

Microwaves

Infrared

Visible

Ultraviolet

X-rays

Gamma rays

The Gamma rays are the shortest wavelength group with frequencies greater than 3 × 10²⁰ Hz.

The Radio waves are the longest wavelength group. Their frequency is lower than 3 × 10⁷ Hz.

The tip of a pencil is about 0.5mm in width.

Calculate the frequency of the wave whose wavelength is about the size of the tip of a pencil i.e. λ = 0.5 mm,

ν = 3×10⁸/(0.5×10⁻³) = 6×10¹¹ Hz.

The infrared rays have frequencies in the range of 3×10¹¹ Hz to 3×10¹³ Hz. So, the wave is infrared.

Infrared waves have a wavelength about the tip of a pencil.

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Answer:

True.

Explanation:

true

knowing your audience there General age gender education level religion language culture and gave group members is the single most important aspect of developing your speech this means the speaker dock smart the audience wasn't often without asking question or spending with any feedback

C.

Explanation:

C. is a gamma ray and they carry the most energy.

The most energy is carried by the gamma rays. The correct option is C.

Gamma radiation, also known as gamma rays, is a type of electromagnetic radiation produced by the radioactive decay of atomic nuclei. It is made up of electromagnetic waves with the shortest wavelengths, which are typically shorter than those of X-rays.

Waves with a higher frequency have more energy. Gamma rays have the shortest wavelengths and highest frequencies of any electromagnetic wave. Gamma rays have more energy than any other electromagnetic wave due to their extremely high frequencies.

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Answer: C

Explanation:

USAtestprep

Answer:

Spring's displacement, x = -0.04 meters.

Explanation:

Let the spring's displacement be x.

Given the following data;

Mass of each shrew, m = 2.0 g to kilograms = 2/1000 = 0.002 kg

Number of shrews, n = 49

Spring constant, k = 24 N/m

We know that acceleration due to gravity, g is equal to 9.8 m/s².

To find the spring's displacement;

At equilibrium position:

Fnet = Felastic + Fg = 0

But, Felastic = -kx

Total mass, Mt = nm

Fg = -Mt = -nmg

-kx -nmg = 0

Rearranging, we have;

kx = -nmg

Making x the subject of formula, we have;

[tex] x = \frac {-nmg}{k} [/tex]

Substituting into the formula, we have;

[tex] x = \frac {-49*0.002*9.8}{24} [/tex]

[tex] x = \frac {-0.9604}{24} [/tex]

x = -0.04 m

Therefore, the spring's displacement is -0.04 meters.

Answer:

magnitude of the Coriolis acceleration is 44.235 ft/s² and the direction of the acceleration is along the axis of transmission

Explanation:

Given the data in the question;

Speed of carousel N = 24 rpm

From the diagram below, selected path direction defines the Axis of slip.

Hence, The Coriolis is acting along the axis of transmission

Now, we determine the angular speed ω of the carousel.

ω = 2πN / 60

we substitute in the value of N

ω = (2π × 24) / 60

ω = 2.5133 rad/s

Next, we convert the given velocity from mph to ft/s

we know that; 1 mph = 1.4667 ft/s

so

[tex]V_{slip[/tex] = 6 mph = ( 6 × 1.4667 ) = 8.8002 ft/s

Now, we determine the magnitude of the Coriolis acceleration

[tex]a_c[/tex] = 2( [tex]V_{slip[/tex] × ω )

we substitute

[tex]a_c[/tex] = 2( 8.8002 ft/s × 2.5133 rad/s )

[tex]a_c[/tex] = 44.235 ft/s²

Hence, magnitude of the Coriolis acceleration is 44.235 ft/s² and the direction of the acceleration is along the axis of transmission

Answer:

Option (A) is correct

Explanation:

a= (vf-vi)/ t

put the values

hence,

a= ( 15-15)/0.01

a=0

Answer:

uv radiation cause cancer

uv radiation effect our eyes

Answer:

you can get

1:skin cancer

2:eye damage

3:skin damage

4:immune system suppression

choose which two u want

hope this helped

:)

Explanation:

Answer:

The answer is "[tex]\bold{7.18 \times 10^3 \ m^2}[/tex]".

Explanation:

The efficiency system:

[tex]\eta =\frac{P_{req}}{P} \times 10\\\\P =\frac{P_{req}}{\eta} \times 10\\\\[/tex]

   [tex]=(\frac{2.20 \times 10^6 \ W}{30})\times 100\\\\=(\frac{220 \times 10^6 \ W}{30})\\\\=(\frac{22 \times 10^6 \ W}{3})\\\\=7.33 \times 10^6 \ W[/tex]  

Using formula:

[tex]A=\frac{P}{I}[/tex]

Effective area:

[tex]A= \frac{7.33 \times 10^6 \ W}{1020\ \frac{W}{m^2}}\\\\[/tex]

   [tex]=\frac{7.33 \times 10^6 }{1020}\ m^2 \\\\ =0.0071862 \times 10^6 \ m^2 \\\\=7.1862 \times 10^3 \ m^2 \\\\[/tex]  

Answer:

The correct answer is option (A) that is KEA > KEB .

Explanation:

Let us calculate -

If the object is straighten up and inclined plane , the work done is

[tex]W=F_d- F_f_r_id-F_gh[/tex]

[tex]W=F_d-\mu_kmgdcos\theta-mgdsin\theta[/tex]

The change in kinetic energy is ,

   [tex]\Delta K=\frac{1}{2}mv^2-\frac{1}{2}m\nu_0^2[/tex]

At the top of the inclined plane , the velocity is zero

So,

[tex]\Delta K=\frac{1}{2} m(0)^2-\frac{1}{2}m\nu_0^2[/tex]

[tex]\Delta KE=-\frac{1}{2}m\nu_0^2[/tex]

From the work energy theorem , we have [tex]W=-\Delta K[/tex] in case of friction , so

[tex]\frac{1}{2}m\nu_0^2=Fd-\mu_kmgdcos\theta-mgdsin\theta[/tex]

[tex]KE=Fd-\mu_kmgdcos\theta-mgdsin\theta[/tex]

For object A-

[tex]KE_A=Fd-\mu_kmgdcos\theta-mgdsin\theta[/tex]

For object B

[tex]KE_B= Fd -2\mu_kMgdcos\theta-2Mgdsin\theta[/tex]

[tex]KE_B= Fd -2(\mu_kMgdcos\theta-Mgdsin\theta)[/tex]

Thus , larger mass is going to mean less total work and a lower kinetic energy .

From the above results , we get

[tex]KE_A >KE_B[/tex]

Therefore , option A is correct .

Answer:

24 J

Explanation:

[tex]K = \frac{1}{2} mv^{2} = \frac{1}{2} (3kg)(4m/s)^{2} = 24 J[/tex]

This question is not complete, the complete question is;

A centroid is an object's geometric center. For an object of uniform composition, its centroid is also its center of mass. Often the centroid of a complex composite body is found by, first, cutting the body into regular shaped segments, and then by calculating the weighted average of the segments' centroids.

An object is made from a uniform piece of sheet metal. The object has dimensions of α = 1.50 ft, where α is the diameter the semi-circle, b= 3.51 ft, and c = 2.20 ft. A hole with diameter d = 0.500 ft is centered at ( 1.21, 0.750 ).

Find x", y", the coordinates of the body's centroid.

Answer:

x" = 1.4857 ft

y" = 0.668 ft

Explanation:

Given the data in the question and as illustrated in the second image below;

from the image;

BC² = DC² - BD²

BC² = 2.2² - 1.5² = 4.84 - 2.25 = 2.59

BC = √2.59 = 1.61 ft

AB = 3.51 ft - 0.75 ft - 1.61 ft = 1.15 ft

so;

A₁ = [tex]\frac{1}{2}[/tex] × 1.51 ft × 1.61 ft  = 1.2075 ft²

x₁ = 0.75 + 1.15 + [tex]\frac{1}{3}[/tex](1.61 ft) = 2.44 ft

y₁ = [tex]\frac{1}{3}[/tex](1.5 ft) = 0.5 ft

A₂ = 1.15 ft × 1.5 ft = 1.725 ft²

x₂ = 0.75 ft + ( 1.15/2 )ft = 1.325 ft

y₂ = ( 1.5/2 ) ft = 0.75 ft

A₃ = [tex]\frac{\pi }{2}[/tex](0.75 ft)² = 0.88 ft²

x₃ = 0.75 - ([tex]\frac{4 }{3\pi }[/tex](0.75 ft)) = 0.43 ft

y₃ = 0.75 ft

diameter d = 0.5 ft and centered at ( 1.21, 0.750 )

A₄ = [tex]\frac{\pi }{4}[/tex]( d )² =  

x₄ = 1.21 ft

y₄ = 0.75 ft

Thus;

x" = [tex]\frac{A_1 x_1 + A_2 x_2 + A_3 x_3 - A_4x_4 }{A_1+A_2+A_3-A_4}[/tex]

so we substitute

x" = [tex]\frac{(1.2075X2.44) + (1.725 X 1.325) + (0.88X0.43) - (0.196 X 1.21 )}{ ( 1.2075 + 1.725 + 0.88 - 0.196 )}[/tex]

x" = [tex]\frac{ (2.9463 + 2.285625 + 0.3784 - 0.23716)}{ 3.6165 }[/tex]

x" = 5.373165 / 3.6165

x" = 1.4857 ft

y" = [tex]\frac{A_1 y_1 + A_2 y_2 + A_3 y_3 - A_4y_4 }{A_1+A_2+A_3-A_4}[/tex]

so we substitute

y" = [tex]\frac{(1.2075X0.5) + (1.725 X 0.75) + (0.88X0.75) - (0.196 X 0.75 )}{ ( 1.2075 + 1.725 + 0.88 - 0.196 )}[/tex]

y" = [tex]\frac{ (0.60375 + 1.29375 + 0.66 - 0.14112)}{ 3.6165 }[/tex]

y" = 2.41638 / 3.6165

y" = 0.668 ft

Therefore,

x" = 1.4857 ft

y" = 0.668 ft

Answer:

[tex]9.495 \times 10^3\ m[/tex]

Explanation:

From the given information:

Using the equation of Barometric formula as related to density, we have:

[tex]\rho (z) = \rho (0) e^{(-\dfrac{z}{H})} \ \ \ \ --- (1)[/tex]

Here;

[tex]p(z) =[/tex] the gas density at altitude z

[tex]\rho(0) =[/tex] the gas density  at sea level

H = height of the scale

[tex]H = \dfrac{RT}{M_ag } \ \ \ --- (2)[/tex]

Also;

R represent the gas constant

temperature (T) a= 280 K

g = gravity

[tex]M_a =[/tex] molaar mass of gas; here, the gas is Oxygen:

∴

[tex]M_a =[/tex] 15.99 g/mol

= 15.99 × 10⁻³ kg/mol

[tex]H = \dfrac{8.3144 \times 280}{15.99 \times 10^{-3} \times 9.8 }[/tex]

[tex]H =14856.43 \ m[/tex]

Now we need to figure out how far above sea level the density of oxygen drops to half of what it is at sea level.

This implies that we have to calculate z;

i.e. [tex]\rho(z) =\dfrac{\rho(0) }{(2)}[/tex]

By using the value of H and [tex]\rho(z)[/tex] from (1), we have:

[tex]\dfrac{\rho(0) }{(2)} = \rho (0) e^{(-\dfrac{z}{14856.43})}[/tex]

∴

[tex]\dfrac{1}{2} = e^{(-\dfrac{z}{14856.43})} \\ \\ e^{(-\dfrac{z}{14856.43})} =\dfrac{1}{2}[/tex]

By rearrangement and taking the logarithm of the above equation; we have:

[tex]- z = 14856.43 \times \mathtt{In}\dfrac{1}{2} \\ \\ -z = 14856.43 \times (-0.6391) \\ \\ z = 9495 \ m \\ \\ z = 9.495 \times 10^3\ m[/tex]

As a result, the oxygen density at  [tex]9.495 \times 10^3\ m[/tex] is half of what it is at sea level.

Answer:

i dont know but i should know try g o o g l e

Explanation:

Answer:

6

Explanation: i looked this up.

According to the Coloumb's law, the force is obtained from the charges and the distance between them is 8.4375×10⁶ N. This force results in the attractive force.

Coloumb's law states the relation between the charges and the distance between the charges. Coloumb's law states that the Force is directly proportional to the product of charges and inversely proprotional to the square of distance between them.

The Coloumb's law gives the force of attraction or repulsion between the charged bodies. Two charges with positive or negative charges repels each other. One positive and one negative charge attract each other.

The force increases with the product of charges increases as product of charges and force are directly proprotional. The force decreases with the increase in distance of seperation and vice-versa. The SI unit of force is newton (N).

The Coloumb's law is:

          F = k (q₁×q₂ / r²)

k is the constant of proportionality and is equal to 9×10⁹ N.m²/C².

q₁, q₂ = charges

r² =  distance of seperation of charges.

From the given,

q₁ = -2C ( negative sign represents the negative charge)

q₂ = +3C ( + sign represents the positive charge)

r² = 80 m ( distance between the charges)

F = k (q₁×q₂ / r²)

  = 9×10⁹×2×3 / 80×80

 = 54×10⁹ / 6400

 = 8437500 N

F = 8.4375×10⁶ N

There is the presesnce of both positive and negative charges, hence it results in the attractive force. Hence, the force F between two charges separated by 80m is  8.4375×10⁶ N.

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Answer:

Explanation:

Stocks give you partial ownership in a corporation, while bonds are a loan from you to a company or government. The biggest difference between them is how they generate profit: stocks must appreciate in value and be sold later on the stock market, while most bonds pay fixed interest over time.

Answer:

Stocks give you partial ownership in a corporation, while bonds are a loan from you to a company or government. The biggest difference between them is how they generate profit: stocks must appreciate in value and be sold later on the stock market, while most bonds pay fixed interest over time.

Explanation:

None

Answer:

A)   v = 40 m / s, B)   v_average = 20 m / s

Explanation:

For this exercise we will use the kinematics relations

A) the final velocity for t = 5 s and since the body starts from rest its initial velocity is zero

         v = vo + a t

         v = 0 + 8 5

         v = 40 m / s

B) the average velocity can be found with the relation

         v_average = vf + vo / 2

         v-average = 0+ 40/2

          v_average = 20 m / s

Answer:

Thrust developed = 212.3373 kN

Explanation:

Assuming the ship is stationary

Determine the Thrust developed

power supplied to the propeller ( Punit ) = 1900 KW

Duct distance ( diameter ; D  ) = 2.6 m

first step : calculate the area of the duct

A = π/4 * D^2

   =  π/4 * ( 2.6)^2  = 5.3092 m^2

next : calculate the velocity of propeller

Punit = (A*v*β ) / 2  * V^2     ( assuming β = 999 kg/m^3 ) also given V1 = 0

∴V^3 = Punit * 2 / A*β

         = ( 1900 * 10^3 * 2 ) / ( 5.3092 * 999 )

hence V2 = 8.9480 m/s

Finally determine the thrust developed

F = Punit / V2

  = (1900 * 10^3) / ( 8.9480)

  = 212.3373 kN

Answer:

a. T = 39.41 N

b. t = 1.76s

c. 150.78 N

Explanation:

Given:

Mass of bucket of water, Mb = 14.6 kg

Mass of cylinder, Mc = 11.1 kg

Diameter of cylinder, D =  0.320 m, or radius, r = D/2 = 0.16m

Displacement of the bucket from the top, that is the vertical displacement , y = 11.0 m

a. The tension in the rope while the bucket is falling is:

F = mg - T = ma

Where F= The force

m= mass

g= Acceleration due to gravity

T = tension in the rope

a = acceleration

T= m(g - a)

Then, calculating the angular acceleration of the pulley system in relation to its radial acceleration

T= 1/2Ma

Merging the two final equation so as to solve for a

M(g - a) = 1/2Ma

Make a the subject of the formula

Mg - Ma = 1/2Ma

1/2Ma + Ma = Mg

a (1/2 M + M) = Mg

Divide both side by (1/2 M + M)

a = Mg ÷ (1/2 M + M)

Inputing the given value in the formula above

g= 9.8m/s2

a = (14.6 kg) (9.8m/s2) ÷ 1/2 (11.1 kg) + 14.6 kg

a = 7.1007m/s2

Now it is easy to input the value into T= 1/2Ma

T = 1/2 (11.1 kg) (7.1007m/s2) = 39.41 N

B. Time of fall is:

Using one of the equation of motion

s = ut + 1/2 at^2

U = Initial velocity

t = time

a = acceleration

s= distance in this case displacement y

making t the subject of the formula

t = √(2s ÷ a)

u is 0 since the bucket starts from rest

so, t = √((2)(11.0 m) ÷ 7.1007m/s2)

t = 1.76s

c.  the force exerted on the cylinder by the axle = T + Mg

  = 42 N + (11.1 kg) (9.8m/s2)

= 150.78 N

Answer:

800joules

Explanation:

work is measured in joules

Answer:

(D) x = 93.8 m

Explanation:

v^2 = v0^2 + 2ax

(20 m/s)^2 = (5 m/s)^2 + 2(2 m/s^2)x

Solving for x,

x = 93.8 m

Answer:

   [tex]r_{cm}[/tex]= 1/5 L

Explanation:

To find the center of mass of the system let's use

        [tex]r_{cm} = \frac{1}{M}[/tex] ∑ r_i x_i

where m is the total mass of the system

let's apply this expression to our case

Let's set the reference frame on the star

         [tex]r_{cm} = \frac{1}{M +4M} ( 4M 0 + M L)[/tex]

         r_{cm} = [tex]\frac{1}{5}[/tex] L

         [tex]r_{cm}[/tex]= 1/5 L

Hey, the breast center is 1/5 of the distance between the star and the planet.